Axial-flow steam-turbine.



C. B. REARICK..

' AXIAL FLOW STEAM TURBINE.

APPLICATION FILED Dnc. 9, 1912.

Patented Nov. 4, 1913.

Z SHEETS-SHEET l.

WITNESSES manners n COLUMBIA PLANGGRAPH cD.,wAsHxNn1'IJN. D. c.

0. B. REARICK.

AXIAL PLOW STEAM TURBINE.

APPLIUATION FILED 1330.9, 1912.

Patented Nov. 4, 1913.

2 SHEETS-SHEET 2.

mann/frs CULUMEIA FLANQURAPH Co., WASHINGTON. D. C.

UNITED sTATEs PATENT orme.

CHARLES BEIVIIS REARICK, OF NEW LONDON, CONNECTICUT, ASSIGNOR T0CONNECTI- CUT TURBINE MANUFACTURING COMPANY, OF

CORPORATION OF CONNECTICUT.`

NEW LONDON, CONNECTICUT, A

AXIAL-FLOW STEAM-TURBINE.

This invention relates to axial flow tur-y bines for use with steam orother elastic motive fluid, the turbine wheels being vpreferably castwith a number of annular series of inclined stepped curved buckets withwhich cooperate suitable nozzle andreturn members provided with curvedreturn passages preferably arranged at dilferentiangles tov assist insecuring the desired increase of area of i the bucket and returnpassagesas the steam passes the desired number of times throughV thevarious wheel buckets. The turbine wheel may also be formed withespecially `arranged expansion spokes of material having generallysimilar expansion to the wheel rim Vwhich may have their inner endssecured to the hub while` the body o-f the spokes is loosely embraced inany desired way by spoke supports which may be cast integral with thewheel hub, if desired. l

In the accompanying drawing showing in a somewhat diagrammatic mannerVan illustrativeembodiment of the invention, Figure 1 is a partial axialsection taken along the line 1 1 of Fig. 2 in'which the wheel bucketsand return passages have been turned up into the line of section to moreclearly show their construction. Fig. 2 is a transverse sectional viewtaken along the line 2-2, 21-2a and the other section lines shownrinFig. 1 to the extent indicated on Fig. 2 so as to show thereinmoreclearly the arrangement of the various sets of wheel buckets and returnpassages. Fig. 3 is a developed flow diagram in which the return membersand passages are shown in dotted section.

In the illustrative embodiment of this invention shown in the drawings,the turbine wheel may be formed in any desired way with the selectednumber of annular series of wheel buckets having the desired form andthe wheel rim and' buckets may be conveniently cast in one piece ofspeciallyl strong bronze or other suitable material as Specicaton ofLetters Patent.

Application led December 9, 1912.

Patented Nov. 4, 191s. Serial No. 735,602. Y

by the process covered by the Hopson and Rearick Patent No. 1,008,478,of November 14, 1911.

Suitable spokes preferably of bronze or other material havingsubstantially the same o-r slightly greater co-e'fiicient of expansionthan the rim material are preferably formed integral with or otherwisesecured to the rimwhich may be conveniently done by casting the rimaround the same, the spokes 26 having as indicated in Figs. l and2suitably formed projections, such as the annu- `lar ribs 37 which arestrongly -gripped by the inclosing portions of the rim material whichvmay have 4suitable inwardly projecting lugs 47 extending from the rim5. The inner ends of these spokes which are preferably formed' withgripping projections such as the annular projections 36 may beconveniently secured to the wheel as by casting the steel, cast iron orother suitable metal used for the hub 48 around them so as to firmlygrip the inner ends of the spokes thus effecting relief of originalcasting strains in rim and spokes; if desired the 'hub metal may extendoutalong the spokes so as to form spoke supports laterally sup portingthe spokes throughout the desired extent while preferably allowing thelongitudinal expansion ofthe spokes beyond the point at which theirinner ends are secured `to the hub. For some reasons it is desirable inorder to insure the accurate alinement of these spokes during suchexpansion as takes place under operating conditions to interpose a spokesleeve 25 of steel or other suitable material around each of the spokes26 before casting the hub metal 48 around the spokes so as to rigidlysecure their inner ends in position, this metal` preferably extendingaround the spoke sleeve throughable admission passage 2 which may becast integral with the casing if desired and within this casing theremay be mounted in any desired way a series of nozzle members and returnpassages each of which may if de-A sired be in the form of an integralcasting 22 having a nozzle tube 3 held in the casing in any desired wayso as to support the nozzle and return member in position in propercooperation with the wheel. f desired suitable alining pins l12 may beformed in the nozzle and return members so as to cooperate with suitablealining sockets, such as 13, in the adjacent members and assist inholding the members in proper circumferential alinement. As shown inFigs. 1 and 3 cach of these nozzle and return members may be providedwith a series of inj ecting nozzles et arranged to copei'ate with thefirst set of buckets 6 in the wheel. These return members 22 may beformed as by casting them integral therein with a number of series ofreturn passages adapted to return the steam received from each set ofwheel buckets into the succeeding set so that the steam is passed thedesired number of times through the wheel buckets to eXert additionalpropelling impulses thereon. As shown in Fig. 2 by the line of arrowsthe steam naturally advances somewhat in the direction of motion of theturbine wheel during its passage axially across the saine through thedifferent series of bucket-s. For this reason the dierent returnpassages in this return member may be arranged in a generally diagonaldirection, it being, however, desirable to arrange special trailing andadvance return passages to receive the steam in the first set of returnpassages7 for instance, when the injecting nozzles are in line with oneof the partitions between the wheel buckets. For this purpose thespecial or trailing return passage 27 may be provided in each returnmember 22 to receive this backwardly di-` verted or backsplit steam anda similar advance return passage 28 may be provided at the other end ofthis first series of' return passages 10. For similar reasons thetrailing return passage 30 and the advance return passage 29 may beprovided at either end of' the similarly shaped ret-urn passages 12 inthe second set. ln the third set the regular return passages are 17 andthe trailing return passage 32 and the advance return passage 31 and inthe fourth set of return passages which may be used in these returnmembers with advantage in some cases the regular return passages are 2Oand the trailing return passage 33 and the ad- Vance return passage 34.'In order to prevent clogging of steam, it is desirable to form theret-urn members 22 so that they are somewhat separated from the adjacentreturn members as by the relief spaces 4:4, l5 and 46. It is desirableto form the annular partitions between the ditlerent sets ot' returnpassages and wheel buckets with curved annular recesses such as a9, 50which serve to receive any surplus steam beyond what can convenientlyenter the succeeding return passage or wheel bucket and curve it aroundso as to again direct it against the inner side into this stream ofmotive fluid.

Tie steam originally injected into the first set of wheel buckets fromthe injecting nozzles t has a high velocity and corspondingly highkinetic energy. At each pass through the wheel buckets the velocity andkinetic energy are reduced so that the stream of' motive fluid thus hasan increased volume at each pass which should be accommodated byincreasing the available ciosssection of the succeeding wheel bucketsand return passages. This can be effectively done by increasing theangle at which the steam is injected into the succeeding sets of bucketsand also by increasing the axial width across the curved row of wheelbuck-` ets or return passages so as to allow a greater width to thecurved stream of steam passing therethrough or if desired thesucceeding.`

set of' wheel buckets for instance may both have an increased angle anda greater width so as to secure through both these factors the desiredincrease-in available cross-section and accommodate the increased volumependicular distance between the partitions* of this set of buckets, thatis, their bucket height correspondingly small. rlhe steam passingthrough this first set of buckets G is under normal operating conditionsdischarged therefrom at a correspondingly greater angle due to itsreduced velocity and the wheel motion and the first set of returnpassages 10 into which the steam passes have their receiving throats orsides 7 arranged as shown in Fig. 1 at a greater angle substantiallyequal to the angle at which the steam is discharged from the first wheelbuckets, as shown in dotted lines in Fig. 2. The steam is with a minimumof disturbance or eddying received and guided around from the returningor injecting sides 8 of these buckets int-o the second set of wheelbuckets 9. This second set of wheel buckets 9 are shown in full lines inthat part of Fig. 2 in which the section is taken along the lines 2 ofFig. 1 and as indicated `the increased angle which these wheel buckets 9make with the wheel circumference at that point correspondinglyincreases the perpendicular distance between the partitions of thisseto-f wheel buckets so as to secure an increased height of buckets andcorresponding increase in their effective area or capacity. The steamfrom the returning sides 8 of the return passages 10 entering thesewheel buckets 9 leaves them at a still greater angle and to receive thissteam under most advantageous conditions the seco-nd set of returnpassages 12 have their receiving ends 11 arranged at substantially theangle of the steam entering from the wheel buckets 9 as shown by thedotted lines in this part of Fig. 2. This set of intermediate returnpassages 12 is preferably` warped so as to guide the steam received intotheir receiving ends 11 at a considerable angle so that when againdelivered into the succeeding set of wheel buckets 14 from the returningsides 13 of these return passages 12 the steam makes a considerably.less angle to the wheel circumference. This is shown quite clearly inthe sectional view through these return passages taken along the line 2bof Fig. 1 which is shown in that part of Fig.

2 which is correspondingly designated. TheV receiving ends 11 of thesewarped return passages are therein indicated in dot and dash lines asbeing in front of the line of section and the steam is shown as beingguided by these warped buckets so as to be discharged from theirreturning sides 13 at a considerably sharper angle so as to properlycoperate with the sharp angle wheel buckets 14. These wheel buckets asindicated in Fig. 1 are given a considerably greater axial width inorder to properly accommodate in their comparatively slight height theincreased volume of steam during this pass through the wheel.V Theincrease in axial width ofthe wheel buckets 9 as compared with the firstset of wheel buckets 6 contributes to their increased carrying capacityas does also their increased angle as compared with the first set ofwheel buckets 6.

As shown in Fig. 2 t-he steam discharged from the wheel buckets 14passes Ainto the dotted receiving ends 15 of the return pasvsages 17which are shown in full rines in the succeeding section on 2c so thatthesteam may be definitely guided around in the same plane in these fiatbuckets 17 so thatwhen discharged from their returning sides 16 it has aconsiderably greater angle and properly enters the fourth set of wheelbuckets 18 which have a correspondingly greater height because of theirgreater angle for which reason their axial width need not be any greaterand may in some cases be even less than the axial width of the wheelbuckets 14. The steam discharged from these wheel buckets 18 is directedin line with the dotted receiving sides 19 of the last set of returnpassages 20, so that when discharged from their returning sides 21 shownin full lines in the section on 2d at the bottom of Fig. 2 the steam isdirected at a very much greater angle to this part of the wheelcircumference, so that the wheel buckets have a much greater height ande'ective area and can properly accommodate the increased volume of thisslower moving steam which is indicated as being discharged directly intothe wheel chamber from this last set of buckets.

By arranging the receiving sides of one or more of the sets of returnpassages at about the angle at which the steam is discharged from thepreceding set of wheel ybuckets the steam is returned to the succeedingset of wheel buckets when each of the return passages is substantiallyiiatata suf,

iiciently greater angle to materially increase the effective area of thewheel buckets when formed with substantially the same axial width andthickness of partition. In this way it is possible to largely or whollyeliminate the use of warped wheel buckets or return passages which areless desirable from the const-ructional standpoint because. of theincreased difficulty of properly forming or finishing them and which aresomewhat undesirable because ofthe increased frictional losses involved.In order to most readily finish wheel buckets or return passages ofthis'character they are preferably formed with somewhat elliptical orflattened curved bottoms so as lto allow the use of a" buiiing orfinishing tool to best advantage. In Fig. 1 the flattened curved bottomsof these bucketsare designated 51, the buckets being sufficientlyshallow to considerably facilitate finishing in this way.

Having described this invention in convnection with a number ofillustrative embodiments, forms, proportions, numbers of parts,arrangements, materials and processes and forming integral spokesupports loosely surrounding said spokes and allowing` their radialexpansion and said plates secured to said rim to inclose said spokes,said Wheel buckets being substantially tlat and a. num

ber of the succeeding sets of said Wheel buckets being arranged at agreater angle to the Wheel circumference than the preceding set, aseries of' return members mounted to cooperate with said wheel, each ofsaid members being provided With a number of sets of curved returnpassages cooperating with the sets of Wheel buckets, one or more setsol" return passages being substantially flat and arranged at a greaterangle than the Wheel buckets from Which they receive fluid.

2. In axial fioW elast-ic fiuid turbines, a cast turbine Wheel rimprovided With a number of annular sets of lapping curved buckets, bronzeexpansion spokes secured to said rim, a Wheel hub being formed of castferrous metal of less co-efficient of' expansion embracing and grippingsaid spokes adjacent their inner ends, said Wheel buckets beingsubstantially flat and a. number ot the succeeding set of said Wheelbuckets being arranged at a greater angle to the Wheel circumferencethan the preceding set, a series of return members mounted to cooperatewith said Wheel, each of said members being provided with a number ofsets of curved return passages cooperating with the sets of wheelbuckets, one or more sets of return passages being substantially fiatand arranged at a greater angle than the Wheel buckets Jfrom which theyreceive fiuid.

3. In axial flow elastic fluid turbines, a cast turbine Wheel rimprovided with a number or" annular sets oit' lapping curved buckets,bronze expansion spokes secured to said rim, a Wheel hub being formed otmetal of less co-eflicient of expansion embracing and gripping saidspokes adjacent their inner ends, said Wheel buckets being substantiallyfiat and a succeeding set of said Wheel buckets being arranged at agreater angle to the Wheel circinnference than the preceding set, aseries of return members mounted to coop-erate with said wheel, each ofsaid members being provided with a number of sets of curved returnpassages cooperating with the sets of Wheel buckets.

et. In axial fiow elastic fluid turbines, a cast bronze turbine Wheelprovided With a number of annular sets of lapping curved buckets, saidWheel buckets being substantially flat and anumber of the succeedingsets oi said Wheel buckets being arranged at a greater angle to thewheel circumference than the preceding set and a number of thesucceeding sets of said wheel buckets having a greater axial Width thanthe preceding set, a series of nozzle and return members mounted tocooperate with said Wheel, each of said members being provided with`cast turbine Wheel provided with a number lof annular sets of lappingcurved buckets, said Wheel buckets being substantially flat and a numberof the succeeding sets of said wheel buckets being arranged at a greatertangle to the Wheel circumference than the `preceding set and asucceeding set of said fivheel buckets having a greater axial Widthithan the preceding set, a series of nozzle vand return members mountedto cooperate with said Wheel, each of said members being provided with aplurality of' inject-ing nozzles to cooperate with the first set ofWheel buckets and with a number of sets of curved return passagescooperating with the succeeding sets of Wheel buckets, one or more setsof' return passages being substantially flat and arranged at a greaterangle than the Wheel buckets from which they receive fluid.

6. In axial flow elastic fluid turbines, a cast turbine Wheel providedWith a number of annular sets of lapping curved buckets, said Wheelbuckets being substant-ially flat and a succeeding set of said Wheelbuckets being arranged at a greater angle to the Wheel circumferencethan the preceding set and a succeeding set of' said Wheel bucketshaving a greater axial Width than the preceding set, a series of nozzleand return members mounted to -cooperate With said Wheel, each of saidmembers being provided With an injecting nozzle to cooperate With thefirst set of wheel buckets and With a number or sets of curved returnpassages cooperating With the succeeding sets of Wheel buckets, one ormore sets of return passages being substantially flat and arranged at agreater angle than the Wheel buckets from which they receive fluid.

7. In axial flow elastic fluid turbines, a turbine wheel provided with anumber of annular sets of lapping curved buckets, said Wheel bucketsbeing substantially flat and a succeeding` set of said Wheel bucketsbeing arranged at a greater angle to the Wheel circumference than thepreceding set, a series of nozzle and return members mounted tocooperate With said Wheel, each of said members being provided with aninjecting nozzle to cooperate with the first set of Wheel buckets andwith a number of sets of curved return passages cooperating with thesucceeding sets of Wheel buckets, one or more sets of return passagesbeing substany tially flat and arranged at a greater 'anglethan theWheel buckets frein which they receive fluid. i

S. In axial flow elastic iiuid turbines, a

turbine Wheel provided with a'numb'er of annularsets of lapping curvedbuckets, said Wheel buckets being substantially flat and a succeedingset of said Wheel buckets being arranged at a greater angle to the Wheelcircumference than the preceding set, a series of nozzle and returnmembers mounted to cooperate With said Wheel, each of said members beingprovided with an injecting nozzle to cooperate With the' lirst set AofWheel buckets and With a number of sets of curved ret-urn passagescooperating with the succeeding sets of Wheel buckets.

9. In axial flow elastic iiuid turbines, a turbine Wheel provided With anumber of annular sets of lapping curved buckets, said Wheel bucketsbeing substantially flat and a number of thesucceeding sets of saidWheel buckets being arranged at a greater angle to the Wheelcircumference than the preced-Y ing set and aV number of the succeedingsets of said Wheel buckets having a greater axial Width than thepreceding set, a series of re turn members mounted to cooperate Withsaid Wheel, each ofsaid membersbeing provided With an injecting nozzleto cooperate with the first set of Wheel buckets and with a number ofsets of curved return passages cooperating With the succeeding sets ofWheel buckets, one or more sets of return passages being arranged todeliver fluid at a greater angle than the wheel buckets from which theyreceive fluid.

10. In axial iioiv elastic fluid turbines, a turbine Wheelr providedwith a number of annular sets of lappingcurved buckets, said wheelbuckets being substantially iat and a number of the .succeeding sets ofsaid Wheel buckets being arranged at a greater angle to the Wheelcircumference than the preceding set, a series of return members mountedto cooperate with said wheel, each of said members being provided withan injecting nozzle to cooperate with the first set of Wheel buckets andwith a set of curvedreturn passages cooperating with the succeeding setof Wheel buckets, one or more sets of return passages being arranged todeliver fluid at a greater angle than the Wheel buckets from which theyreceive fluid.

11. vIn axial flow elastic iui'd turbines, a turbine Wheel provided witha number of annular sets of lapping curved buckets, saidl Wheel bucketsbeing substantially flat and? a number of the succeeding sets of saidWheel buckets being arranged at a greater angle to the wheelcircumference than the-preceding set.

12. In axial'flovv elastic fluid turbines, a turbine Wheell pro-videdWith a number of annular sets of lapping curved buckets, said Wheelbuckets being'substantially flat and a succeeding setof said Wheelbuckets being arranged at a greater angle to the Wheel circumferencethan the preceding set.

13. In axial flovv elastic fluid turbines, a turbine Wheelv providedwith a number of annular sets of lapping curved buckets, a succeedinglset of said Wheel buckets being arranged at a greater angle to theWheel circumference than thefpreceding setf 14. In axial tiotv elasticfluid turbines, a turbine Wheel provided with .a number of annular setsof lappingcurved buckets, a succeeding set :of said Wheel buckets beingarranged at a greater angle to the Wheel circumference than. thepreceding set and a succeeding set of said Wheel buckets having agreater axial Width than the preceding set.

15. In axial flow elastic fluid turbines, a turbine Wheel provided Witha number of annular sets of lapping curved buckets, there being annularcurved recesses in the edges of the `partitions separating the dif-vferent sets of buckets, a return member mounted to cooperate with saidWheel, and provided with a number of'sets ofv curved return passagescooperating With the 'sets of Wheel buckets, there being annular curvedrecesses formed in the edges of the partitions betyveen the differentsetsv of return passages.

16. In axial flow elastic fluid turbines,l a turbine Wheel provided WithaV number of. annular sets of lapping curved buckets, a succeeding setof said Wheel buckets being arranged at a greater angle to the Wheelcircumference than a preceding set, there being annular curved recessesin the edges of the partitions separating the different sets of buckets,a return member mounted to `cooperate With said Wheel, and provided witha number of sets of curved return passages cooperating with the sets ofWheel buckets, there being annular curved recesses formed in the vedgesof the partitions between the dierent sets of return passages.

17. In axial flow elastic fluid turbines, a turbine Wheel provided Witha number of annular setsof lapping curvedbuckets, a succeeding setofsaid Wheel buckets being arranged at a greaterangle to the Wheelcircumference than a preceding set, there being annular curvedrecessesin the edges of the partitions separating *the different sets ofbuckets, a return member mounted to cooperate with said' Wheel, andprovided with a number of sets of curved return passages cooperatingvvith the sets of Wheel buckets.

1S. In axial-flow elastic--fluid turbines, a

`*turbine Wheel provided with a number of annular sets of lapping curvedbuckets, a

succeeding set of said wheel buckets beingV arranged at a greater angleto the wheel circumference than a preceding set, a return member mountedto cooperate with said wheel, and provided with a number of sets ofcurved return passages cooperating with the sets of wheel buckets, therebeing annular curved recesses formed in the edges of the partitionsbetween the different setsV of return passages.

19. In axial flow elastic fluid turbines, a cast turbine wheel providedwith a number of annular sets of lapping curved buckets, there beingannular curved recesses in the edges of the partitions separating thedifferent sets of buckets, a series of cast integral nozzle and returnmembers mounted to cooperate with saidY wheel, each of said membersbeing provided with a plurality of injecting nozzles to cooperate withthe first set of wheel buckets and with a number of sets of curvedreturn passages cooperating with the succeeding sets of wheel bucketsand advancing substantially diagonally across said wheel, there beingannular curved recesses formed in the edges of the partitions betweenthe different sets of return passages and there being relief spacesbetween adjacent members to allow premature escape of retarded motivefluid from said wheel buckets.

20. In axial flow elastic fluid turbines, a turbine wheel provided witha number of annular sets of lapping curved buckets, there being annularcurved recesses in the edges of the partitions separating the differentsets ot buckets, a series of nozzle and return members mounted tocooperate with said wheel, each of said members being provided with aninjecting nozzle to cooperate with the first set of wheel buckets andwith a number of sets of curved return passages cooperating with thesucceeding sets of wheel buckets and advancing substantially diagonallyacross said wheel, there being annular curved recesses formed in theedges of the partitions between the different sets of return passagesand there being relief spaces between adjacent members to allowpremature escape of retarded motive fluid from said wheel buckets.

2l. In axial flow elastic fluid turbines, a turbine wheel provided witha number of annular sets of lapping curved buckets, a series of' nozzleand return members mounted to cooperate with said wheel, each of saidmembers being provided with an injecting nozzle to cooperate with thefirst set of wheel buckets and with a number of sets of curved returnpassages cooperating with the succeeding sets of wheel buckets andadvancing substantially diagonally across said wheel, and there beingrelief spaces between adjacent members to allowpremature escape ofretarded motive fluid from said wheel buckets.

22. In axial tlow elastic fluid turbines, a turbine wheel provided witha number of annular sets of lapping curved buckets, a series of nozzleand return members mount ed to cooperate with said wheel, each of saidmembers being provided with an injecting nozzle to cooperate with thefirst set of wheel buckets and with a set of curved return passagescooperating with the succeeding set of wheel buckets and there beingrelief spaces between adjacent members to allow premature escape ofretarded motive fluid from said wheel buckets.

23. In axial flow elastic fluid turbines, a turbine wheel provided witha number of annular sets of curved buckets, a series of re turn membersmounted to cooperate with said wheel, each of said members being provided with a number of sets of curved return passages cooperating withthe succeeding sets of wheel buckets and advancing substantiallydiagonally across said wheel, there being relief spaces between adjacentmembers to allow premature escape of' retarded motive fluid from saidwheel buckets.

24. In axial flow elastic fluid turbines, a turbine wheel provided witha niunber of annular sets of curved buckets, a series of return membersmounted to cooperate with said wheel, each of said members beingprovided with a set of curved return passages cooperating with thesucceeding set of wheel buckets, there being relief spaces betweenadjacent members to allow premature escape of retarded motive fluid fromsaid wheel buckets.

25. In axial flow elastic fluid turbines, a cast turbine wheel providedwith a number of annular sets of lapping curved buckets, a series ofnozzle and return members mounted to cooperate with said wheel, each ofsaid members being provided with one or more injecting nozzles tocooperate with the first set of wheel buckets and with a number of setsof curved return passages cooperating with the succeeding sets of wheelbuckets and advancing substantially diagonally across said wheel, therebeing trailing return passages formed in said return members arrangedbehind the nozzle cooperating with such members and there being reliefspaces between adjacent members to allow premature escape of returnedsteam from said wheel buckets.

26. In axial flow elastic fluid turbines, a cast turbine wheel providedwith a number of annular sets of lapping curved buckets, a series ofnozzle and return members mounted to cooperate with said wheel, each ofIsai-d members being provided with one or more injecting nozzles tocooperate with the first set of wheel buckets and with a number of setsof curved return passages cooperating With the succeeding sets of Wheelbuckets, there being trailing return passages formed in said returnmembers arranged behind the nozzle coperat-ing With such members, andthere being relief spaces between adjacent members to alloW prematureescape of returned steam from said Wheel buckets.

27. In axial floW elastic fluid turbines, a cast turbine Wheel providedWith a number of annular sets of lapping curved buckets, a series ofseparate nozzle and return members mounted to coperate With said Wheel,each of said members being provided With one or more injecting nozzlesto cooperate With the first set of Wheel buckets and With a set ofcurved return passages cooperating With the succeeding set of Wheelbuckets, there being trailing return passages formed in said returnmembers arranged behind the nozzle cooperating With such members.

28. In axial floW elastic fluid turbines, a cast turbine Wheel providedWith a number of annular sets of lapping curved buckets having flattenedcurved bottoms, a plurality of injecting nozzles to coperate With oneVset of buckets and return members provided With a number of sets ofcurved return passages cooperating With succeeding sets of Wheelbuckets, said Wheel buckets being substantially flat and a number of thesucceeding sets of said Wheel buckets being arranged at a greater angleto the Wheel circumference than the preceding set and a number of thesucceeding sets of said Wheel buckets having a greater axial Width thanthe preceding set, one or more sets of return passages beingsubstantially flat and arranged at a greater angle than the Wheelbuckets from Which they receive motive fluid and one of said sets ofreturn passages being Warped and arranged to return the fluid to theWheel buckets at a less angle to the Wheel circumference than said fluidWas received to pass the motive iiuid a numberof times through saidWheel buckets at progressively increasing angles and to reduce the angleof returning fluid before again passing it through the Wheel buckets atprogressively increasing angles.

29. In axial iioW elastic fluid turbines, a turbine Wheel provided Witha number of annular sets of lapping curved buckets, a plurality ofinjecting nozzles to cooperate With one set of buckets and returnmembers provided With a number of sets of curved return passagescooperating With succeeding sets of Wheel buckets, said Wheel bucketsbeing substantially flat and a number of the succeeding sets of said.Wheel buckets being arranged at a greater angle to the Wheelcircumference than the preceding set, one or more sets of returnpassages being substantially flat and arranged at a greater angle Y thantherWheel buckets from Which they receive motive fluid and one of saidsets of return passages being Warped and arranged to return the fluid tothe Wheel buckets at a less angle to the Wheel circumference than saidiuid Was received to pass the motive fluid a number of times throughsaid Wheel buckets at progressively increasing angles and to reduce theangle of returning fluid before again passing it through the Wheelbuckets at progressively increasing angles.

30. In axial oW elastic fluid turbines, a turbine Wheel provided With anumber of annular sets of lapping curved buckets, a plurality ofinjecting nozzles to coperate With one set of buckets and return membersprovided With a number of sets of curved return passages cooperatingWith succeeding sets ofl Wheel buckets, a number of the succeeding setsof said Wheel buckets being arranged at a greater angle tothe Wheelcircumference than the preceding set, vone or more sets of returnpassages being substantially flat and arranged at a greater angle thanthe Wheel buckets from Which they receive motive fluid and one of saidsets of return passages being Warped and arranged to return the fluid tothe Wheel buckets at a less angle to the Wheel circumference than saidfluid Was received to pass the motive fluid a number of times throughsaid Wheel buckets at progressively increasing angles and to reduce theangle of returning fluid before again passing it through the Wheelbuckets at progressively increasing angles.

3l. In axial iioW elastic fluid turbines, a turbine Wheel provided Witha number of annular sets of lapping curved buckets and a series of castnozzle and return members mounted to coperate Withv said Wheel each ofsaid members being provided With a plurality of injecting nozzles tocooperate With one set of said Wheel buckets and With a number of setsof curved return passages cooperating With succeeding sets of Wheelbuckets, oneor more of said sets of return passages being substantiallyflat and arranged at a greater angle to the adjacent Wheel circumferencethan the'preceding set to progressively increase the angle at YWhich themotive fluid is injected into the different sets of Wheel buckets. j

32. In axial floW elastic fluid turbines, a turbine Wheel provided Witha number of annular sets of lapping curved buckets and a series ofreturn members mounted to cooperate With said Wheel each of said membersbeing provided With a number of sets of curved return passagescooperating With succeeding sets of Wheel buckets, one or more of saidsets of return passages being substantially flat and arranged at agreater angle to the adjacent Wheel circumference than the preceding setto progressively increase the angle at which the motive fluid isinjected into the diiferent sets of Wheel buckets.

33. In axial flouT elastic fluid turbines, a turbine Wheel provided witha number of annular sets of lapping curved buckets and a series ofreturn members mounted to cooperate with said Wheel each of saidmenibers being provided with a number of sets of curved return passagescooperating With succeeding sets of Wheel buckets, one or more of saidsets of return passages being arranged at a greater angle to theadjacent Wheel circumference than the preceding set to increase theangle at which the motive fluid is injected into the didercnt sets ofWheel buckets.

34. In axial floiv elastic fluid turbines, a turbine Wheel provided witha number of annular sets of lapping curved buckets and a series ofreturn members mounted to cooperate with said Wheel each of saidinembers being provided with a number ot sets ot' curved return passagescooperating with succeeding sets of Wheel buckets, one or more ot saidsets of return passages being arranged at a greater angle to the acentWheel circumference than the preceding set to increase the angle atwhich the motive fiuid is injected into the succeeding` set of Wheelbuckets.

35. ln axial flow elastic fluid turbines, a cast turbine Wheel providedwith a number of annular series of lapping curved buckets havingflat-tened curved bottoms and coperating injecting nozzles and returnpassages, a number of sets of said buckets making a greater angle to thewheel circumference than the preceding set and one or more of said setsof Wheel buckets having a greater axial Width than the preceding set.

36. 1n axial flow elastic fluid turbines, a turbine Wheel provided witha number of annular series of lapping curved buckets, a set of saidbuckets making a greater angle to the wheel circumference than thepreceding set and one or more of said sets of Wheel buckets having agreater axial Width than the preceding set.

37. ln axial flow elastic fluid turbines, a turbine Wheel provided witha number of annular series of lapping curved buckets, a set of saidbuckets making a greater angle to the wheel circumference than the gre`ceding set.

3S. ln axial flouv elastic fluid turbines, a turbine Wheel provided witha number of annular sets of lapping curved buckets, a number of sets ofsaid buckets being arranged at a greater angle to the Wheelcircumference than a preceding set and a series of return membersmounted to cooperate with said Wheel and advancing substantiallydiagonally across said Wheel, each of said return members being providedwith a great-er axial Width and being substantially flat and arranged ata greater angle to the Wheel circumference than the preceding set.

89. ln axial flow elastic fiuid turbines, aV

turbine Wheel provided with a number ot annular sets of lapping curvedbuckets and a series of return members mounted to cooperate with saidWheel each of said return members being provided Vith a number of setsof curved return passages cooperating with the sets of Wheel buckets,one or more sets of said return passages having greater axial ividti andbeing arranged at a greater angle to the Wheel circumference than thepreceding set.

s0. ln axial fioiv elastic fluid turbines, a turbine ivlieel providedwith a number of annular sets of lapping curved bucket-s and a series ofreturn members mounted to cooperate Witli said Wheel each of said returnmembers being provided with a. number ot sets of curved return passagescoperating wit-li the sets of Wheel buckets, one or more sets of saidreturn passages being arranged at a greater angle to the wheelcircumference than the preceding set.

41. In elastic fluid turbines, a cast Wheel rim :formed of bronze havinghigh co-eflicient of expansion and provided ivitli integrally castbucket partitions and buckets, a plurality of sets of substantiallyradial bronze expansion spokes having high coeflicient of expansionsecured to said rim, said spokes having ends formed with proj ections tobe inclosed and gripped by inwardly projecting lugs cast on said rim, aWheel hub secured to the inner ends of said expansion spokes, the innerends of said spokes being provided with projections and said hub beingformed of cast ferrous metal of less coefticient of expansion'embracingand gripping said spoke ends and forming integral spoke supports looselysurrounding said spo-kes and allowing their radial expansion, spokesleeves cast in said spoke supports and guiding said spokes in theirradial eXpansion and side plates secured to said rim to inclose saidspokes.

42. ln elastic fluid turbines, a cast Wheel rim formed of bronze havinghigh co-etiicient of expansion and provided with integrally cast bucketpartitions and buckets, substantially radial bronze expansion spokeshaving high co-cfficient of expansion secured to said rim, said spokeshaving ends formed with projections to be inclosed and gripped byinwardly projecting lugs caston said rim, a Wheel hub secured to theinner ends of said expansion spokes, the inner ends of said spokes beingprovided With projections and said liub being formed of cast ferrous`metal of less co-eiiicient of expansion einbracing and gripping saidspoke ends and forming integral spoke supports loosely surrounding saidspokes vand allowing their radial expansion, spoke sleeves cast in saidspoke supports and guiding said spokes in their radial expansion. a

43. In elastic fluid turbines, a cast wheel rim having high co-eiiicientofV expansion and provided with integrally cast bucket partitions andbuckets, substantially radial expansion spokes having high co-eiiicientof expansion secured to said rim, said spokes fhaving ends formed withprojections to be inclosed and gripped by inwardly projecting lugs caston said rim, a wheel hu-b secured to the inner ends of said expansionspokes, the inner ends of said spokes being provided with projectionsand said hub being formed of cast metal of less co-elficient ofexpansion embracing and gripping said spoke ends and forming integralspoke supports loosely surrounding said spokes and allowing their radialexpansion.

44. In elastic fluid turbines, a cast wheel rim having high co-eliicientyof expansion and provided with integrally cast bucket partitions andbuckets, substantially radial eX- pansion spokes having highco-eiiicient of expansion secured to said rim, said spokes having endsinclosed and gripped by said rim and a wheel hub secured to the innerends of said expansion spokes, said hub being formed of metal of lessco-efficient of eX- pansion and having spoke supports looselysurrounding said spokes and allowing their radial expansion.

45. In elastic fluid turbines, a cast wheel tions and buckets,substantially radial ein pansion spokes having high co-eliicient ofexpansion secured to said rim, and a wheel hub secured to the inner endsof said eXpansion spokes, said hub being formed of metal of lessco-efiicient of expansion and having spoke supports partly surroundingsaid spokes and allowing their radial expansion.

46. In elastic fluid turbines, a cast wheel rim having high co-eflicientof expansion and provided with integrally cast bucket partitions andbuckets, expansion spokes having high co-efiicient of expansion securedto said rim, and a wheel hub secured to the inner ends of said expansionspokes, said hub being formed of metal of less co-eficient of expansion.

47. In elastic fluid turbines, a wheel rim having high co-efhcient oflexpansion and provided with bucket partitions and buckets, substantiallyradial bronze expansion spokes having high co-efficient of expansionsecured to said rim, a wheel hub secured to the inner ends of saidexpansion spokes, the inner ends of said spokes being provided withprojections and said hub being formed of cast ferrous metall of lessco-efli'cient of expansion embracing and gripping said inner spoke endsand forming integral spoke supports loosely surrounding said spokes andallowing their radial expansion and spoke sleeves cast in said spokeysupports and guidingsaid spokes in their radial' expansion.A

4S. In elastic iuid turbines, a wheel rim having high co-eflicient j ofexpansion andy provided with bucket partitions and buckets,substantially radial expansion spokes.V have ing high co-eflicient ofexpansion secured to said rim, a wheel hub secured to the inner ends ofsaid expansion spokes, said hub being formed of cast metal of lesscia-efficient ofvveXpansion embracing and gripping said inner spoke endsand forming integral spoke supports loosely surrounding said spokes andallowing their radial expansion, and spoke sleeves cast in said spokesupports and guiding said spokes in their radial expansion. f

4:9. In elastic fluid turbines, a wheel rim having high coefficient ofexpansion and provided with bucket partitions and buckets, substantiallyradial expansion spokes having high co-eflicient of expansion secured tosaid rini, a wheel hub secured to the inner ends of said expansionspokes, said hub being.

formed of cast metal of less co-eflicient of expansion forming integralspoke supports loosely surrounding the inner portions of saidspokes andallowing their radial eX pansion, and spoke sleeves cast in said spokesupports and guiding said spokes in their radial expansion. Y v

50. In elastic fluid turbines, a turbine wheel comprising substantiallyradial spokes of cuprous metal, a cast wheel riinlhaving substantiallythe same coeiiicient of eXpansion as said spokes and provided withbucket partitions and buckets and cast around the outer ends of saidspokes and a wheel hub of ferrous metal cast around the inner ends ofsaid spokes to effect close engagement and union therewith and allow theoriginal casting strains in said rim to become relieved by cooling thesame before connecting said hub there-to.

5l. In elastic fluid turbines, a turbine wheel comprising spokes ofwrought cuprous metal, a cast'wheel rim provided with bucket partitionsand buckets and castV around the outer ends of said spokes and a Vwheelhub cast around the inner ends of said spokes to effect close engagementand union therewith and allow the original casting strains in said rimto becomeA relieved by cooling the saine before connecting said hubthereto.

52. In elastic fluid turbines, a turbine wheel comprising substantiallyradial spokes of wrought bronze metal, a cast wheel rim havingsubstantially the same coeflicient of expansion as said spokes andprovided with bucket partitions and buckets and cast around theouterends of said spokes and a Wheel hub of ferrous metal cast around theinner ends of said spokes to effect close engagement and union therewithand allow the original casting strains in said riln to become relievedby cooling the same before connecting said hub thereto.

53. In elastic fluid turbines, a turbine wheel comprising spokes ofWrought metal, a cast Wheel rim provided with bucket partitions andbuckets and castaround the outer ends of said spokes and a Wheel hubcast around the inner ends of said spokes to allow` the original castingstrains in said rini to become relieved by cooling the 'same beforeconnecting` said hub thereto.

54. lnelastic Huid turbines, a turbine Wheel comprising` spokes, a castWheel rim substantially the `same coefcient of expansion as said spokesand provided with bucket partitions and buckets and cast around theouter ends of said spokes and a Wheel hub attached to said spokes toallow the .original casting strains on said rim to become relieved bycooling before connecting said hub thereto.

55. ln elastic fluid turbines, a turbine Wheel comprising spokes, a castWheel rim provided lWith bucket partitions and i turbine buckets andcast around portions of said spokes, and a Wheel hub secured to theinner ends of said spokes to allow the original casting strains on saidrim to become relieved by cooling the same before connecting. said hubthereto.

56. In elastic iiuid turbines, a cast Wheel rim having high coefficientof expansion and provided with integral bucket partitions and turbinebuckets, expansion spokes liaving high coefficient of expansionextending inward from said rim, a Wheel hub cast around the inner endsofsaid expansion spokes, said hub being formed of cast metal of lesscoetlicient of expansion.

57. ln axial flow elastic fluid turbines, a turbine wheel provided witha number of annular sets of lapping curved buckets, a series of nozzleand return members mounted to cooperate with said Wheel, each of saidmembers being provided with an in jecting nozzle to cooperate with thefirst set of Wheel buckets and with a number of sets of curved returnpassages cooperating with the succeeding sets of Wheel buckets andvadvancing substantially diagonally across said Wheel.

58. In axial flow elastic fluid turbines, a turbine Wheel provided witha number of annular sets of lapping curved buckets and a series ofreturn members mounted to cooperate with said Wheel and advancing sub#stantially diagonally across said wheel each of said return membersbeing provided with a number of sets of curved return passagescooperating With the sets of wheel buckets, one or more sets of saidreturn passages being arranged at a greater angle to the Wheelcircumference than the preceding set-.L

CHARLES BEMS REARXCK.

lVitnesses:

HARRY L. DUNCAN, Jnssin B. KAY.

Copies of this patent may be obtained for five cents each, byaddressingthe Commissioner of latents, Washington, D. C.

